Proborhyaena is an extinct genus of proborhyaenidae Sparassodonta that lived during the Oligocene of South America. It is considered to be the largest of the sparassodonts.
Description
Proborhyaena was very large in size, with the skull alone reaching up to ,
and the whole animal may have been as large as a present-day
spectacled bear.
Sorkin (2008) speculated that
Proborhyaena gigantea may have weighed up to ,
but subsequent studies consider this an overestimate and argue that it would have weighed up to .
Proborhyaena was a massive animal, with a robust and powerful body. Its skull was equipped with a short, high snout, and its caniniform teeth were saber-shaped, although not as developed as those of the later Thylacosmilus. The canines, in contrast to those of Thylacosmilus, which had an "almond-shaped" section and a sharp margin, were ovoid in cross-section and thus would have been much more robust. Like the thylacosmilids, Proborhyaena possessed only one pair of lower incisors.
Classification
Proborhyaena was first described by Florentino Ameghino in 1897, based on fossils found in Patagonia in deposits dating to the Late Oligocene (Deseadan). Subsequently, more fossils ascribed to this species were found from the Salla Formation of Bolivia,
Proborhyaena is the eponymous genus of the family Proborhyaenidae, also including smaller forms such as Callistoe and Arminiheringia these animals belonged to the sparassodonts, a group of metatherian mammals akin to marsupials that in South America occupied the ecological niches typical of other carnivorous mammal groups on other continents. Proborhyaena may have been the largest carnivorous metatherian that ever lived.
Paleobiology
Proborhyaena is thought to have been a poor runner that probably did not chase prey over long distances for extended periods; it probably fed on large, slow-moving prey, such as Pyrotherium. Both Proborhyaena and numerous large ungulates became extinct during the Oligocene; it is likely that this predator-prey ratio was influenced by climate change.
